The present invention relates to conveyor idlers and especially to the combination of conveyor idlers and their terminal bearings and for mounting the conveyor idlers to a conveyor for supporting a conveyor belt or the like.
In the past, it has been common to provide troughing idlers for conveyor belts and these included flexible troughing idlers of the suspension type. Flexible troughing idlers of the suspension type have achieved commercial success as substitutes for a previously conventional type of troughing idler having rigid rollers mounted on fixed axes. One such flexible troughing idler of the suspension type includes that illustrated in U.S. Pat. No. 3,876,890 which provides for an idler structure molded on a wire cable in which the wire cable is held to each end by two terminal conventional metal bearings and in which the molded rollers are molded from neoprene. One disadvantage of this prior art idler is that it requires a great variety of mounts to fit each of many types of conveyor belts which require different vertical and horizontal adjustments of the outer ends of the idlers. The location of the supported ends of the idlers determines the curvature of the trough formed by the conveyor belt. Variations of the type of material to be conveyed frequently calls for various trough depths and curvatures. In installations using previous conventional composite troughing idlers formed of individual rotatable rollers, adjustment of the outer ends of the outer rolls was seldom provided for and any desired degree of troughing was determined by the angularity of the axis of the end rollers with respect to the permanent horizontal axes of the intermediate roller. Since the rollers have rigid inflexible axes, adjustment of the ends to vary troughing curvatures is a necessity on a radius determined by the roller length. With the advent of the flexible, suspension type troughing idlers, adjustment of the suspension point became more feasible. In my prior U.S. Pat. No. 3,033,352 for a Conveyor Idler Mounting Means and Support, I provided an adjustable support for the outer extremities of idler support rollers for conveyor belts of a flexible suspension type troughing idlers which provided for a lateral adjustment to be automatically affected as an incident to the vertical adjustment. These prior art flexible troughing idlers and mounts have worked satisfactorily for many years, but the rise in the cost of raw materials has substantially increased the price of the terminal bearings and thereby substantially increased the cost of suspension troughing idlers and their supporting systems. It is accordingly one advantage of the present invention to provide a molded conveyor idler and terminal bearing combination which is easily formed of polymer materials for providing the necessary strength to support conveyor belts for long periods without failure. In addition to the increased economy, the use of plastics in the bearings allows the bearings to operate without lubricants or with water as a lubricant thereby providing idlers and terminal bearings more suitable in the food industry. It has been widely considered in the conveyor idler field that plastic bearings would not be sufficiently strong to support idlers. Through the utilization of predetermined plastics along with specially designed terminal support bearing structures interconnected with steel members, a conveyor idler and bearing combination can be provided with sufficient strength to support conveyor belts over long periods without failure.